I presume this is the right place to post this. Ever since I've had my computer it clicks a few times on startup/restart. Always been the way for years. However, on booting Debian 8 last night I noticed it did it a few times more than usual and stopped when the desktop had loaded. However, the boot to desktop speed was fine, very fast.

Normally I would think this noise is coming from the platters in the hard drive or the arm, but my main hard drive is an SSD. However, I also have two backup platter hard drives. Any idea what this could be? Could it be from the drives or elsewhere?

Lysander wrote:Normally I would think this noise is coming from the platters in the hard drive or the arm...

That would be my first thought, as well.

Lysander wrote:Could it be from the drives or elsewhere?

Absolutely!

That is to say, it "could" be anything, and HDD or not-HDD ("elsewhere") are the only alternatives. Only way to know is to test, and at the risk of pointing out the obvious, the only person who can test is you.

But before you test, make sure you have backed up any crucial data from your mechanical drives. Clicking HDD is usually a sign of imminent bad things. Act as if the drive is about to fail catastrophically any moment now.

After that, pop open your case and pull the power cables from all the mechanical drives. Boot. If you hear a click, you know it's "elsewhere." Otherwise, connect each HDD (one at a time) and reboot until you identify the offending drive. If it were me, I'd retire that drive and keep it only as emergency backup.

Thanks for the advice. I am pretty sure it's not the hard disks. I am going guess it's one of two things - the PSU or the optical drives. It sounds like the optical drives do when they look for disks.

On boot later today I will see if it clicks again. If not, I probably won't do anything.

If it does, I will move to stage 2 or plan [yes, stage 1 is not doing anything] and start listening to see where it could be coming from in the computer. That will then give me an area to concentrate on should I want to start pulling leads out!

But I am currently thinking it is something other than the hard drives.

That's a pretty antagonistic reaction! Your response was actually highly valued. What I meant was: if the problem does not continue, then of course there's no reason to further investigate [my "stage 1" comment was meant to be humourous, sorry it didn't work]. Of course, if the problem does continue later today I will investigate as per your advice. Thanks anyway, whether you can now access this post or not.

EDIT: In the end this was a CD left in one of the optical drives. Glad it was such a simple solution. Forgot I had left it there from the Mint install.